<form name="add-mark" method="post" action="<?php echo $this->basepath();?>/mark/add"  enctype="multipart/form-data">
    <input type="hidden" name="subject" value="photo" /><!-- photo|video -->
    <input type="hidden" name="subject_id" value="1" />
    <div>
        Add mark
        
        <div id="error">
             <span></span>
          </div>
          
         <div id="mark_div">
              Mark
              <input type="number" name="mark" placeholder="Mark"/>
         </div>
        
         <div id="description_div">
              Comment
              <textarea name="comment" rows="8" cols="40" placeholder="Comment"></textarea>
         </div>
    </div>
    <button id="validatebutton">Post mark</button>
</form>